All four implementations now support:
- --account N flag: bypasses env vars, loads credentials from accounts.csv row N
- UNSANDBOX_ACCOUNT env var: selects default CSV row (fallback to row 0)
- accounts.csv fallback: tries ~/.unsandbox/accounts.csv then ./accounts.csv
- Correct priority: explicit flags > --account N > env vars > CSV row 0
AWK: Added load_accounts_csv() with native getline, GLOBAL_ACCOUNT_INDEX
variable, pre-scan loop in END block for --account/-p/-k global flags.
COBOL: Added GET-CREDENTIALS paragraph with shell-based CSV resolution,
WS-ACCOUNT-INDEX variable, --account N parsing at start of MAIN-PROCEDURE,
all HANDLE-* paragraphs now PERFORM GET-CREDENTIALS instead of inline
credential fetching.
Forth: Added account-index variable, load-accounts-csv-index word, sarg
shifted-arg accessor, arg-shift variable, --account N detection in main.
All handler N arg calls replaced with N sarg to support the shift.
Prolog: Added load_accounts_csv/3 predicate with file I/O, nb_setval/nb_getval
for account_index global, --account N pattern matching in main/1,
get_public_key/1 and get_secret_key/1 now check account_index before env vars.